1. Field of the Invention
The invention relates to a plant for extracting electric energy from water power.
2. Description of Related Art
Knowledge exists of many devices that utilize the potential drop of water or its kinetic energy in order to convert electric energy therefrom. In this context, a differentiation is basically made between two plant types.
According to a first plant type, the kinetic energy of the onflowing water is utilized in order to thereby drive a generator for power generation. To this end, provision is made for flow-impinged components, such as turbine blades, which are impinged upon by a flow of water and set in motion thereby. Water power plants of the first type are found in run-of-the-river power stations or storage power stations. The undershot water wheel is also operated in this way.
According to a second plant type, the kinetic energy of the onflowing water is not primarily used, but rather its released potential energy during the execution of a potential drop. That is to say, according to this principle the gravitational force of the water, which acts upon a flow-impinged component, drives a drive element. This principle is used in the case of the overshot water wheel, for example.
In the present invention, the term “extraction of electric energy” is used. This term is synonymous to the frequently used terms such as “energy conversion”, “power generation” or “energy production”.
EP-A-1 731 756 describes a water power plant, for example, in which the potential energy of water is used for the conversion of electric energy. The plant includes a water power unit with a vertical chute and an electric power generator, which is connected to the water power unit. Blades, which are fastened to a chain and receive a specific volume of water, are arranged in the chute. As a result of the weight of the water which bears upon the blades, the chain, and via this, an electric power generator, are driven. The plant is comparatively inflexible with regard to its application capabilities since this can only be designed together with a vertical chute.
WO 2011/041918 also describes a plant for the conversion of electric energy from water power, and comprises a circulating drive chain with a load run and a return run. The drive chain is guided in a circulating direction around two deflection elements that are arranged in an offset manner to each other, both horizontally and vertically. The drive chain comprises a multiplicity of flow-impinged components, which are arranged one behind the other in the circulating direction and spaced apart. The flow-impinged components in each case form part of a chain link of the drive chain. On the side of the load run, the flow-impinged components engage in an inclined water conveying duct and, with the duct sidewalls and the duct bottom, form water receiving compartments. In an inlet region, the individual water receiving compartments receive a specific volume of water, which is only released again from the water receiving compartment in the outlet region.
Furthermore, the plant comprises a generator for the conversion of electric energy from the circulating drive chain. The water, at a higher-located inlet region, is fed into the water conveying duct, wherein the blades, which are immersed in the water conveying duct, retain the inflowing water in the formed water receiving compartments. The blades are driven by the weight force of the water, as a result of which the water in the receiving compartments is guided along the water conveying duct to a lower-located outlet opening. The described solution has the disadvantage that the blade guiding in the water conveying duct is rather inaccurate so that the receiving compartments are too permeable in the movement direction for the water being carried along and some of the water being carried along flows down the water conveying duct to the outlet region without being utilized. In addition, the installation of the plant is also comparatively complex and intricate. Furthermore, the energy conversion is not implemented in an optimum manner.